One of the biggest storylines entering the 2014 season will be the loss of Mariano Rivera. Since 1997, the Yankees have implemented the best closer in the history of the sport. Following his retirement, the organization didn't have to look far to find his replacement. Since 2009, David Robertson was groomed to be Rivera's replacement, and in 2011, Robertson took the most out of playing with Rivera by learning the cutter and copying the closer's mechanics.

Robertson finished 2011 with a 1.08 ERA, a 13.5 K/9, and even a few MVP and Cy Young votes. Since then, Robertson's strikeout numbers have remained high, and his command has improved drastically. Where he used to own a BB/9 in the upper-4's, Robertson averaged a 2.6 BB/9 over the last two seasons. Robertson's 2.34 ERA over the last two years, and improvements in strikeouts, ground balls, and command, have convinced the Yankees that their next great closer is David Robertson.

Robertson's cutter has grown closer to Rivera's yearly, but the pitch is still significantly different. One of Robertson's great abilities is in the spin rate of his pitches, which is evident in the dramatic movement of his curveball. His cutter also generates a good amount of spin, but the movement still does not match Rivera's. Robertson averages about an inch less of movement into left-handed hitters, with about 3 to 4 inches more of vertical rise. This results in a good amount of strikeouts and low line drive rates, but it also accounts for some high home run rates.

Fortunately, Robertson also has the curveball as an out pitch. There are times when the reliever gets too cutter happy, but when he mixes in his curveball, hitters usually look lost. In 2014, Robertson should try to find a better way to mix these two pitches, and use more of the breaking pitch than the 30% usage we saw in 2013. This should help increase strikeouts and lower home run rates.

Robertson has 8 career saves and 10 career blown saves, and many Yankee fans are worried about how he'll handle the pressure of closing and filling in for Rivera. Inevitably, Robertson will blow a save in 2014, and Yankee crowds aren't known for their forgiving nature. It's possible that he'll struggle to adapt to the situation, but it's also notable that Robertson spent the last four seasons pitching in high leverage situations for this same team. As I mentioned above, the right-hander was built to close in New York. He's a high strikeout and low contact-type pitcher, and with the ability and experience in New York taken into account, he was likely the best candidate over any of the free agent choices.

With Robertson taking over the closing duties full time, I expect some blown saves and disappointment, but having sat next to Mariano Rivera over the last six seasons, I'd bet Robertson learned more than a cutter from the great closer. Robertson has shown that he can keep his head in high-leverage spots, and I don't expect him to fall without getting back up. I'll put Robertson at a 2.50 ERA with a 2.50 FIP. Robertson may give up a few more hits, but I expect him to challenge more hitters in 2014, lowering his walk rates to the low 2's, and perhaps even winning more of those battles which will increase his strikeout numbers. Will he succeed as closer? Yes. Will he be Mariano Rivera? No.